1. Field of the Invention
This invention relates to a circuit interrupter operating mechanism, and more particularly it pertains to means for rapidly opening the contacts of a circuit interrupter.
2. Description of the Prior Art
Certain types of circuit interrupters, such as the so-called "puffer" circuit breaker, have involved relatively slow contact-opening time periods. Attempts to reduce the opening times have been made with some success. For example, U.S. Pat. Nos. 2,096,619, 2,436,194, 2,476,024, and 2,552,358 disclose typical means for expediting the opening and/or closing of contacts in circuit breakers.
Inasmuch as circuit breakers of this type involve the use of various mechanical linkage systems, it is necessary to initiate movement of the system as soon as possible when an overcurrent occurs. When an overcurrent occurs, most mechanical devices for initiating the opening of contacts have been found unsatisfactory simply due to the time lost in applying forces once the signal to open occurs, i.e., dwell time. Indeed, more recent innovations using electrical primers, although usually faster, still involve an ignition time which is slower than desirable. Thus, the so-called "bridge-wire" type of primer, comprising a resistance wire which ignites a propellant directly involves a relatively slow ignition time of one to three milliseconds. Faster ignition times are desirable in order to open contacts when overcurrents occur.